The episode is a crossover between Doctor Who and its spin-off series Torchwood (2006) and The Sarah Jane Adventures (2007). Writer Russell T. Davies described the crossover by saying "it's simply doing what kids do in their imaginations ... they would think nothing of having their Dalek toys battling Star Wars droids. Why not have all the factions of the Doctor Who universe going into battle together?".
The Stolen Earth is the first appearance of Davros since the 1988 serial Doctor Who: Remembrance of the Daleks: Part 4 (1988). Russell T. Davies postponed Davros' return as he thought that "Davros would dominate the Daleks... like plain robots, instead of the scheming geniuses that they are", and used the previous series to establish the Daleks' individual intelligence.
Margaret Blaine, the Slitheen who was reverted back to an egg in season one was due to make a cameo in a scene with the Shadow Proclamation, and Annette Badland even recorded a line of dialogue but the scene was cut.
The scene depicting Wilfred Mott firing a paint ball pellet at a Dalek was inserted at the suggestion of Bernard Cribbins; he thought it would provide comic relief in between heavy exposition. Cribbins explained that impairing their vision would be "common sense" owing to the Daleks' lack of limbs and cycloptic nature. The Dalek's response - evaporating the paint ball and replying "My vision is not impaired" - removed a weakness the Daleks had exhibited since their first appearance in Doctor Who: The Dead Planet (1963).